1. Field of the Invention
The present invention relates to a document placement device provided in an image reader device such as a copying apparatus, facsimile and the like, and more specifically relates to a document placement device suitable for accommodating book-like documents for image reading and image reader device provided with said document placement device.
2. Description of the Related Art
There are various conventional document placement mechanisms used in image reader devices for copying apparatus, facsimiles and the like. One such document placement mechanism maintains a document with the surface to be read pressed against the bottom of a glass plate used as a glass platen.
In such a document reading mechanism, the surface of the document to be read is optically exposed and read from above, such that the operation can be performed while the document surface to be read is visible from above through the glass platen. Accordingly, the document can be easily positioned, thereby reducing the reading errors.
However, the aforesaid document placement mechanism provides that the document surface to be read is placed in direct contact with the glass platen such that the reading surface is flat. Therefore, when a document is set on the document placement mechanism, the document surface to be read and the surface of the glass platen must be pressed into a state of mutual contact. Specifically, the document must be pressed against a stationary glass platen from the underside, or the glass platen must be pressed against the placed document from above. Therefore, a serious disadvantage occurs in the case of reading many pages of a bound document such as a book, inasmuch as the glass platen and document must be separated each time the reading of each open page is completed to turn the pages.
Furthermore, in the case of documents in book form, the first pages and last pages shift with the thickness of the book, i.e., the gutter (binding portion) of the book at the center area between the right and left open pages shifts as the thickness of the turned pages accumulating on right and left sides changes, such that a bulging deformation is produced in the pages to be read.
An object of the present invention is to eliminate the previously described disadvantages by providing a document placement device which holds the surface to be read of a open book-like document in a flat state, and corrects shifting of the center position (binding portion) of said open document, and a document reader device provided with said document placement device.